My first post. Just need a few suggestions.

[dvcrogers]

Hi everyone. Thanks for letting me be a part of such a great forum. I am hoping you guys/gals can help me out just a bit.
I have a set for Fountek FR88-ex and a set of Peerless SLS 6.5" woofers. I am wondering if it would be possible to use those drivers to build a small set-up for my home office that would sound better than something I can buy at Best Buy or the like? (I am willing to use a tweeter too, just not sure which one-Dayton maybe)
If so, can somebody recommend a box and crossovers? For my first build, I think I should stick to just trying to build the box and x-overs instead of designing too. I am affraid to royally screw it up and then get discouraged. (I have had a couple of engine projects take that route)

Anyway, thanks for the help.

Dave Rogers

[Mark65]

Which Peerless woofers do you have? Some of their 6.5's aren't really suited to bass duties in a three way. It might be that you have two sets of mids, and need a woofer and a tweeter.

Also, some design goals, room size, usage plans, etc. will be helpful.



Welcome!


Mark

[Wolf]

Which Peerless woofers do you have?

These:
http://www.madisoundspeakerstore.com...-woofer-4-ohm/



Mark- I think they'll suffice.

New-dude- I think the FR88 in a small sealed box, or even using it as a mid/tweeter in the same cabinet as the SLS will likely be alright.

Later,
Wolf

[dvcrogers]

Hey Wolf, thanks for the reply. Mark, those are the ones. Any idea on a cabinet size? As for design goals, just something simple. I would like to achieve something that sounds better than the discount type stuff at the big box stores. The room is 10'x12'.

[Pete Schumacher ®]

Hey Wolf, thanks for the reply. Mark, those are the ones. Any idea on a cabinet size? As for design goals, just something simple. I would like to achieve something that sounds better than the discount type stuff at the big box stores. The room is 10'x12'.

You definitely have the foundation for something that could easily match/exceed most things you'd find in a Best Buy. The key is getting the crossover right, and that takes a bit of work.

A small format tweeter is all you'd need to finish things off. The Dayton ND16 is probably plenty, crossed at 4000Hz. And being small, it will allow you to get it close to FR88. The FR88 probably could go full range, but you'd lose a lot of detail off axis without the tweeter.

And a quick look at the specs on that woofer, and I'd think that the 1cf PE MTM cabinet would be about right, allowing you enough space for the FR88 to have its own sealed chamber, and enough volume left for a vented enclosure for the woofer (.5cf and 40Hz tune).

[DanP]

Hi everyone. Thanks for letting me be a part of such a great forum. I am hoping you guys/gals can help me out just a bit.
I have a set for Fountek FR88-ex and a set of Peerless SLS 6.5" woofers. I am wondering if it would be possible to use those drivers to build a small set-up for my home office that would sound better than something I can buy at Best Buy or the like? (I am willing to use a tweeter too, just not sure which one-Dayton maybe)
If so, can somebody recommend a box and crossovers? For my first build, I think I should stick to just trying to build the box and x-overs instead of designing too. I am affraid to royally screw it up and then get discouraged. (I have had a couple of engine projects take that route)

Anyway, thanks for the help.

Dave Rogers

I've simulated a couple crossovers for the Fountek and the Dayton ND20FB-4 that turned out really nice on paper at least. Where do you plan to put them? -on a bookshelf, against a wall, on a desk, all of the above, etc? If you let me know, I can just alter one of my sims for the right amount of BSC for your situation. I would also recommend throwing both of those woofers in an enclosure with an amp for subwoofer duty as opposed to making a 3-way out of them. That will allow the main speakers to be much smaller and eliminate the complexity and expense of the 3-way crossover at the expense of the cost of a plate amp (I think the SA70 is $60).

Dan

[dvcrogers]

Thanks Pete and Dan.
Dan, I think at this point I would need to mount the speakers on the wall. I like the idea of doing a separate sub box. That is doable. You guys have got me thinking that I could morph this project into a cheap 5.1 system in the near future. That would be kinda cool. This will be run off of a JVC RX-6018V.

So...Dan, (and everyone else)I would like to hear more. GEEZ-I haven't even started yet and the project has grown. Haha.

[Steve Henry]

Thanks Pete and Dan.
GEEZ-I haven't even started yet and the project has grown. Haha.

You have no idea!

[Mark65]

I actually think that woofer will be better served crossing to the mid in the same cabinet. It does indeed look stout, and could cross fairly high, but as a sub, I'd guess it would be pretty easy to locate with the FR88 needing to cross around 100Hz, at least. I could easily be wrong though, and certainly have been before.

I'll do whatever I can to help, though....



Mark

[dvcrogers]

I know that the FR88s do not play well much below 300hz. (I had bought the FR88s and the SLS to use in my truck with a crossover point of 350 hz in mind)

[fastbike1]

There are other possibilities for the Fountek that you're not likley to hear on this forum.
You might also try here:
http://www.diyaudio.com/forums/full-range/

A key phrase to use would be a FAST alignment.

I know that the FR88s do not play well much below 300hz. (I had bought the FR88s and the SLS to use in my truck with a crossover point of 350 hz in mind)

[DanP]

If you make a sealed box to house the FR88 and the ND20FB-4 that is 5"W x 7"H x 5"D you should be able to mount it on the wall quite easily. 1/2" stock is plenty for the box and in fact preferred for a little more breathing room inside. A 4" x 6" piece of fiberglass wall insulation shoved to the back should serve for stuffing/absorbing. Mount the tweeter 2" from the top and 2" from one side and the woofer 4.5" from the top and 2.5" from the side (don't forget to mirror image the tweeters).

Then use the schematic below for the crossover and you should get something like the attached simulated frequency response which tries to incorporate a best guess for the effect of hanging the speakers on the wall. That's what the 5dB dip centered around 900Hz is all about. Hanging speakers on a wall will almost always result in this type of dip, but I'm a believer in putting your speakers where you want them and then dealing with the consequences. The wall mounting actually helps a bit with the efficiency and the low end extension.

You can see the FR88 only gets down to about 150Hz on the wall, so you'll probably lowpass the subwoofer between 100-150Hz depending on what sounds best. And, yes, there will be some localization of the subwoofer, but besides going to a 3-way, this is probably your best option. A 3-way would probably not be able to be hung on the wall very effectively.

A 200uF capacitor in series with the woofer before the crossover will knock down the low bass input to the FR88 without changing the overall FR, but you may be able to use the high level input and output on the SA70. I'm not sure how well that option works or what value of cap they have in there for the highpass, but it may be worth a try.

If this looks like a path you want to continue down, I can model the sub for you as well.

Dan

[dvcrogers]

Thanks for the info Dan. I will dig into this when I get off work. It looks very interesting.